I am very curious to know how it is going with your next Boomonator Saturnus
BTW nice projects all!
Also depends on whether you're outdoors or indoor. And the 2 parameters are actually mutually exclusive, so you have to decide what is low enough bass for a certain SPL, or the other way around.
The 11½ liter per speaker used here is optimized for the very specific design parameters for this bipolar ground placed speaker that provides maximum linearity down to about 100 Hz.
You can make it go deeper if you like but you need a 3 times larger cabinet and you lose 3dB in sensitivity, and would need to redesign the whole thing. Bipolar operation wouldn't be a good choice in that case either.
I am very curious to know how it is going with your next Boomonator Saturnus
BTW nice projects all!
After using one year my old ghettoblaster i've decided to start a new ghettoblaster project. The old one weighing 26.5kgs i have decided to make the new one lighter so it would be used more often. My goal is to get it under 10kgs weight.
Ive already decided to use 2 or 4(probably only two):
P. Audio WN-8R http://www.paudio.ru/downloads/WN-8S.pdf 1.3kg, 94dB/W
or
P. Audio WN-10R http://www.paudio.ru/downloads/WN-10S.pdf 1.6kg, 96dB/W
as the bass driver.
Im going to change the 2x 18ah 12V lead-batteries into dealextreme.com 20x 18650-lithium-ion batteries or RC few LiPo-batteries. Reducing 6kg batteryweight to about 1kg. The plywood will also change from 12mm pine to 9mm and 6mm birch plywood with lightening traces. Im also planning on putting a 70-80Hz highpass filter, because i finally understood that it is nonsense trying to go down below 80hz with a ghettoblaster Also the tunging frequenzy will raise from 60Hz-->80Hz. The amp will remain the same Sure-electronics TK2050 2x100W
What are your opinions on those bass drivers? For a amateur like me the seem very good. I would also be very happy if someone could recommend some good tweeters to go with those bass drivers. Doesn't need to be piezo, can be a horn tweeter as well, or anything that is suits well for ghettoblaster use.
Thanks for your replies in advance!
Ive already decided to use 2 or 4(probably only two):
P. Audio WN-8R http://www.paudio.ru/downloads/WN-8S.pdf 1.3kg, 94dB/W
or
P. Audio WN-10R http://www.paudio.ru/downloads/WN-10S.pdf 1.6kg, 96dB/W
as the bass driver.
Im going to change the 2x 18ah 12V lead-batteries into dealextreme.com 20x 18650-lithium-ion batteries or RC few LiPo-batteries. Reducing 6kg batteryweight to about 1kg. The plywood will also change from 12mm pine to 9mm and 6mm birch plywood with lightening traces. Im also planning on putting a 70-80Hz highpass filter, because i finally understood that it is nonsense trying to go down below 80hz with a ghettoblaster
Also the tunging frequenzy will raise from 60Hz-->80Hz. The amp will remain the same Sure-electronics TK2050 2x100WWhat are your opinions on those bass drivers? For a amateur like me the seem very good. I would also be very happy if someone could recommend some good tweeters to go with those bass drivers. Doesn't need to be piezo, can be a horn tweeter as well, or anything that is suits well for ghettoblaster use.
Thanks for your replies in advance!
How do you want to connect 20 of the LiIon batteries? For the TK2050 I would suggest going 8sXp (8 in series, x parallel). That would give you 33.6 V fully charged. Keep in mind, that the LiIons output 4.2V on full charge.
Also for using these batteries in parallel packs, I would take unprotected ones. You wouldnt even notice if one battery goes into protection, and the pack would just run on one of the parallel rails. On the other hand the protection can mess things up in a parallel-series config (read that somewhere)
Keep an eye on your voltage level, or get some smarter protection-board! Also you will need some sort of battery case (which is not commercially available). I got myself a handful of battery cases from dealextreme as a starting point, but they are not connected yet either ...
I am hoping that the ta2024 board stops working at 9.0 V which would be an intrinsic protection for my 3s2p config. Will have to check that sometimes
Also check this out: 9800 12V LiIon for 20$
greets
rob
Also for using these batteries in parallel packs, I would take unprotected ones. You wouldnt even notice if one battery goes into protection, and the pack would just run on one of the parallel rails. On the other hand the protection can mess things up in a parallel-series config (read that somewhere
)Keep an eye on your voltage level, or get some smarter protection-board! Also you will need some sort of battery case (which is not commercially available). I got myself a handful of battery cases from dealextreme as a starting point, but they are not connected yet either ...
I am hoping that the ta2024 board stops working at 9.0 V which would be an intrinsic protection for my 3s2p config. Will have to check that sometimes
Also check this out: 9800 12V LiIon for 20$
greets
rob
-Is it normal with a little hum in the speakers when the signal source (iphone) is paused?
-Is it ok or dangerous to just unplug the signal source when playing or should you always break the power to AMP6 before? I guess this can be a problem since most people will be drunk when this thing is used and i don´t want to harm the amp.
-Is it ok or dangerous to just unplug the signal source when playing or should you always break the power to AMP6 before? I guess this can be a problem since most people will be drunk when this thing is used and i don´t want to harm the amp.
An iPhone, yes. Real mp3players, no, unless you are charging it while playing then there will be background noise.
Never had a problem although it certainly doesn't sound good. But frankly it's more dangerous to the mp3player than the amp.
The 41hz I made are dead quite, but the iphone has a decent DAC and output stage (for is kind) so I have no ideas as to your hum. Do you have signal wiring close to power wiring or the tripath chip or board in general (it emits some EMI as it is a switching device).
I'm fairly sure you can eventually damage the amp inputs or even your speakers (they are very sensitive so the spike damage them more than normally). As for all electronics, always power of when (dis)connecting unless it is designed for hot-swap.
I'm fairly sure you can eventually damage the amp inputs or even your speakers (they are very sensitive so the spike damage them more than normally). As for all electronics, always power of when (dis)connecting unless it is designed for hot-swap.
I've bought a cheap Tepai-TA2020 and I would like to change the input resistors for mp3, can anyone tell me, which resistors I should use? And where can I buy them?
It already have a mp3 input, does it have a lower resistance than the other input?
Lepai TRIPATH TA2020 Class T Amp Hi-Fi Audio Amplifier on eBay (end time 13-Jun-10 10:49:02 BST)
Thank you.
It already have a mp3 input, does it have a lower resistance than the other input?
Lepai TRIPATH TA2020 Class T Amp Hi-Fi Audio Amplifier on eBay (end time 13-Jun-10 10:49:02 BST)
Thank you.
Hmmm? I was thinking my hum is because i use unpolarized 0.22 film-type input-caps, but this should not be a problem as i have asked Jan over at 41hz.
Maybe it is because my speaker cables are routed over and to close to the board?(the outgoing hole in the case is just over the signal input...) i will try and change their route this weekend and report back.
BTW: my DC-offset is 12.4mV and 20.5mV, is this difference normal?
Maybe it is because my speaker cables are routed over and to close to the board?(the outgoing hole in the case is just over the signal input...) i will try and change their route this weekend and report back.
BTW: my DC-offset is 12.4mV and 20.5mV, is this difference normal?
The DC offsets are normal, even up to 150mV can be considered acceptable.
The humming is probably due to a wrongly referenced ground.
-The chip should be isolated from the heatsink.
-The board grounds should all be isolated from the case (this you can measure with your dmm)
-The source/signal ground should be isolated from the case.
In some cases it can help to connect the PGND to the case through a 10R resistor, 100nF cap and two large diodes in two directions. Bundle them all in parallel and use this as the single one and only connection between PGND and the case/earth.
What is PGND?
With a single supply voltage amp this is the negative of the largest electrolytic cap(s)...
Good luck!
I have decided to go for the RC-Lipos and use a prober charger/balancer. Would have been too big hassle to do the wirings and charging cables for 20x18650 lithiums.How do you want to connect 20 of the LiIon batteries? For the TK2050 I would suggest going 8sXp (8 in series, x parallel). That would give you 33.6 V fully charged. Keep in mind, that the LiIons output 4.2V on full charge.
Also for using these batteries in parallel packs, I would take unprotected ones. You wouldnt even notice if one battery goes into protection, and the pack would just run on one of the parallel rails. On the other hand the protection can mess things up in a parallel-series config (read that somewhere
Keep an eye on your voltage level, or get some smarter protection-board! Also you will need some sort of battery case (which is not commercially available). I got myself a handful of battery cases from dealextreme as a starting point, but they are not connected yet either ...
I am hoping that the ta2024 board stops working at 9.0 V which would be an intrinsic protection for my 3s2p config. Will have to check that sometimes
Also check this out: 9800 12V LiIon for 20$
greets
rob
I have no clue on proper pa-tweeters that would match these P.Audio WN-8R-woofers well. So i would be very pleased if someone could recommend a good tweeter with about the same SPL as the woofer (94dB/w)and a nice spread. Looking at the frequency response below. I assume that a crossover cutting at 1800hz would be good for the woofer?
P. Audio WN-8R:
An externally hosted image should be here but it was not working when we last tested it.
Looks like P. Audio WN-8R is the best choice for low weight, OK sound and high SPL and reasonable price. I have been looking for some alternatives, but havent found anything promising yet. If you have any better option for under 100€ in your mind, please mention.
Im going to have 21litres box for each woofer, keeping the size of the blaster acceptable. I did some simulation in WinISD, and tried 90Hz, 95Hz and 100Hz tuning. How does the tuning look like:
http://i78.photobucket.com/albums/j114/wehlami/ghettoblaster2010.jpg ?
If i connect the woofer and tweeter in parallel on both channels, it makes them appear as 4ohm load to the amplifier? Thus giving me more output from the amp? Ofcourse i have to put the crossover somewhere between, but would it work?
I would be very happy if someone can anwser these questions so i can get my project going on
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Ahh thanks. okay. I bought a fiiO E3 mp3 amplifier just for fun in case it didn't play loud enough. I have no idea how it will work. It's supposted to amplify the signal from a mp3 player to headphones (with impedance about 16 ohm)!?
What do you think?